/*
 * Copyright 2009 original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.configleon.resource;

import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.core.io.Resource;
import org.springframework.util.StringUtils;

public abstract class AbstractPropertyResources implements PropertyResources, ApplicationContextAware {
    
    private Log logger = LogFactory.getLog(AbstractPropertyResources.class);

    private ApplicationContext applicationContext;

    private String overrideJvmVariableName = "configPropertiesOverride";

    /**
     * @param resources The list of resources.
     * @param location The location of the resource.
     */
    protected void addResource(List<Resource> resources, String location) {
        Resource resource = applicationContext.getResource(location);
        
        if (logger.isInfoEnabled()) {
            logger.info("Trying to add resource " + location);
        }

        if (resource != null && resource.exists()) {
            resources.add(resource);
            if (logger.isInfoEnabled()) {
                logger.info("Adding resource " + location);
            }
        }
    }

    public List<Resource> getResources(String configLocation)
            throws FileNotFoundException {

        List<Resource> resources = new ArrayList<Resource>(1);

        String configPropertiesOverride = System.getProperty(overrideJvmVariableName);
        if (StringUtils.hasText(configPropertiesOverride)) {
            if (logger.isInfoEnabled()) {
                logger.info("The " + overrideJvmVariableName + " JVM variable is " + configPropertiesOverride);
            }
            addResource(resources, configPropertiesOverride);
        }
        
        return resources;
    }

    protected ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    public void setApplicationContext(ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }

    protected String getOverrideJvmVariableName() {
        return overrideJvmVariableName;
    }

    /**
     * Allow the jvm variable name to be configured (by Spring)
     */
    public void setOverrideJvmVariableName(String overrideJvmVariableName) {
        this.overrideJvmVariableName = overrideJvmVariableName;
    }
}
